Oils and gasoline are consumed in great volumes, and thus are often stored in large tanks which are not necessarily well protected by a guard. In view of this, especially when considering the situation of crude oil being stored at wellheads in an isolated area, the problem of theft has been significant for many years.
Numerous proposals have been suggested for ways of marking crude oil, gasoline, or other solvents with a dye, for example Cassidy U.S. Pat. No. 2,046,365, or coded powders as disclosed in Meloy U.S. Pat. No. 3,861,886.
However, disadvantages are found in all of the previously proposed systems. For example, it may well be necessary to remove coded powders from the oil product before using it. Also the identification of the coded powders requires at least a microscope and perhaps other, more complicated machinery. There is always the possibility that other particulate matter could be present in the oil or gasoline, with the result that accurate identification might be difficult.
With respect to dyes, there is the wide perception that it is better for the dye to be substantially invisible while present in the oil or gasoline, being rendered visible by some process of identification. Many of these identification processes are complicated chemical reactions requiring specialized reagents and equipment.
There is a need for an oil or gasoline tagging material which is not readily detectable while residing in the oil, but in which one can demonstrate its presence by an easy detection technique, which can be performed at isolated wellheads and other remote areas.
In accordance with this invention, an oil identification system is provided in which the oil itself may show no apparent trace of the identification system present. However, when it is desired to identify the oil, it can be easily and unambiguously done by the simplest of procedures, requiring no special reagents or equipment, and easily performed in the field or anywhere else.